No abstract is provided for this article.
Abstract In our attempts to develop nucleoside analogues with selective antiviral activity we have envisaged the following targets : viral DNA polymerase (whether or not via viral dThd kinase), reverse transcriptase, AdoHcy hydrolase, dTMP synthetase, OMP decarboxylase and CTP synthetase
By the techniques of interferon induction in primary rabbit kidney cells "superinduced" with metabolic inhibitors, ultraviolet absorbance-temperature profiles, sensitivity to pancreatic ribonuclease A, and sucrose velocity gradient ultracentrifugation, a number of reactions between double-helical RNA and single-stranded RNA or DNA homopolymers were investigated. The polymers involved in these studies were poly(adenylic acid), poly(uridylic acid), poly(ribothymidylic acid), poly(5-bromouridylic acid), poly(deoxythymidylic acid), poly(deoxyuridylic acid), poly(3-methyluridylic acid), poly(2'-O-methyluridylic acid), and poly(2'-azido-2'-deoxyuridylic acid). Two different reaction courses, both leading to the formation of triple helices, were noted: (1) poly(Ux)-poly(A) + poly(Uy) leads to poly(Ux)-poly(A)-poly(Uy) if the Tm of poly(Ux)-poly(A) was higher than the Tm of poly(Uy)-poly(A); (2) poly(Ux)-poly(A) + poly(Uy) leads to poly(Uy)-poly(A)-poly(Ux) if the Tm of poly(Ux)-poly(A) was lower than the Tm of poly(Uy)-poly(A). In these equations, the homopolymer written to the left of poly(A) implies Watson-Crick hydrogen bonding whereas the polymer to the right of poly(A) is involved in Hoogsteen hydrogen bonding.
No abstract is provided for this article.
Antiviral chemotherapy has come of age. Several compounds, i.e. amantadine, rimantadine, idoxuridine, trifluridine, vidarabine, acyclovir, ribavirin and azidothymidine, have been licensed for clinical use and other promising compounds may follow soon. The search for new antiviral agents has been boosted by the advent of AIDS, but the activity spectrum of the newly developed antivirals not only spans retroviruses but also various other virus infections, i.e. herpes-, adeno-, pox- and rhinovirus infections. Clinical trials have been started with a variety of these new compounds and the prospects for an effective chemotherapy of several viral diseases certainly look bright.
The neplanocin A analogs, 3-deazaneplanocin A, 9-(trans-2',trans-3'-dihydroxycyclopent-4'-enyl)adenine (DHCA), and 9-(trans-2',trans-3'-dihydroxycyclopent-4'-enyl)-3-deazaadenine (DHCDA), all potent inhibitors of S-adenosylhomocysteine (AdoHcy) hydrolase, were studied for their broad-spectrum antiviral potential. 3-Deazaneplanocin A, DHCA, and DHCDA proved specifically effective against vesicular stomatitis virus, vaccinia virus, parainfluenza virus, reovirus, and rotavirus. Their selectivity was greater than that of neplanocin A, particularly against vesicular stomatitis virus and rotavirus. As could be expected from adenosine analogs that are directly targeted at AdoHcy hydrolase, 3-deazaneplanocin A, DHCA, and DHCDA were fully active in adenosine kinase-deficient cells, implying that their activity did not depend on phosphorylation by adenosine kinase. None of the AdoHcy hydrolase inhibitors showed selective activity against human immunodeficiency virus (type 1). 3-Deazaneplanocin A at a dose of 0.5 mg/kg per day conferred marked protection against a lethal infection of newborn mice with vesicular stomatitis virus.
In this paper a real-time control and optimization system for laser flame cutting of thick plates of mild steel is presented. The proposed system consists of two subsystems, namely a process monitoring and a control and optimization module. The process monitoring module evaluates the cut quality by measuring a set of sensing parameters, which are well-correlated with different quality characteristics of the cut surface. The applicability of different optical sensors (photodiodes and a NIRcamera) has been investigated. An overview of the most suitable set of sensing parameters is presented. The correlations between different quality deteriorations and the sensing parameters are mentioned as well as the reasons for these correlations. The real-time control and optimization module is implemented as an expert system with a dual functionality. On the one hand, it compares the sensing parameters with predefined thresholds and assigns one of the predefined quality classes to the instantaneous cut quality. On the other hand, it modifies the cutting parameters based on the predefined set of interpretable rules corresponding to the identified quality class. The obtained results prove the effectiveness of the chosen approach in terms of increased autonomy, productivity, and efficiency of the process, as well as elimination of the need for manual quality control and the possibility to automatically generate quality reports.
Abstract Bei unserer Suche nach neuen Virustatika haben wir 2.3(1H,4H)‐Chinoxalindion‐Derivate synthetisiert und auf ihre antivirale Aktivität gegen verschiedene Stämme des Virus Herpes Simplex Typ 1 und Typ 2, gegen Vaccinia Viren und gegen Vesicular Stomatitis Viren getestet. Keine der Verbindungen zeigte eine signifikante antivirale Aktivität im Vergleich mit 5‐Ethyl‐2′‐desoxyuridin (EtUdR).
